The United States, South Korea and Japan are sniffing the air in a coordinated intelligence effort to determine what type of nuclear device was detonated by North Korea. Their previous underground nuclear tests, in 2006 and 2009, drew on limited reserves of plutonium. Any evidence highly enriched uranium was used this time would signal that North Korea has developed a second source of fissile material, expanding its potential warhead capabilities and raising the risk that the cash-strapped nation may sell such uranium to would-be nuclear weapons states such as Iran. President Barack Obama and Japanese Prime Minister Shinzo Abe vowed in a phone call Wednesday to thwart North Korea's nuclear and ballistic-missile programs, the White House said. In another development, the United States will support an international push at next month's UN Human Rights Council to look into human rights conditions in North Korea, U.S. officials said.

SYRIA: Rebels moving on airport

Syrian rebels brought tanks, mortars and homemade rockets to bear Wednesday in their offensive to seize the international airport in Aleppo and a nearby military airport, a day after making other strategic gains in the northern region. The opposition fighters, seeking to cut off supply lines to President Bashar Assad's forces guarding the airports, were able to gain partial control of railroads in the area, activists said. Taking the airport would be a significant gain and could solidify the opposition's hold on the province of Aleppo.

AUSTRALIA: A death in Israeli prison

Foreign Minister Bob Carr said Thursday his government was notified through security channels of the arrest of an Australia-Israeli citizen in Israel in 2010 on security charges months before he died. Israel admitted for the first time Wednesday that it held the man under a false name for security reasons and that he died in prison more than two years ago. The case raised questions about Israel's Mossad agency.